X a apparatus for concentrating sulfurio acid by means of



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5 1,894. FIG- .4 TTOH/ YS.

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f' JACQUES A'L' oUisKEssLER, ,or 'cnE-RMoN'T--Fnannnm FRANCE,

APPARTUs-Foa CONCENTRATINGSU'LEURIC' Acm BY MEANS or HEATED e/isiisfV V'fsPEcIrIeArioiv roam-1g part ofLettersPa/tent No.' 520,994, dated Jene 5, 1894'. Y r`/iippiicaniminedrecentere,1891. sananet-14.585. (Nomade.)

h To all, whom ifm/ay concern A,

Be it I rnown that LJAGQUES LOUIS Kassy L EI, a citizen of the Republic of France,*re 'siding in .Clermont-Ferrand, (luyde-Dme,)V Francefhave'inventedcertain Improvements in and Apparatus for the Concentration of Sulfuric Acid by'Means of Heated Gases, of which the following is a specification; -Th'e apparatus is specially arranged-for employing h ot gases for evaporating the sulfuric acid by direct contact, employing by prefererence gases charged with sulfurous acid. In Iaddition to the parts employed for eecting the production and movement off the hot gases and which present no novelty except in their connectiomand the refrigerator for the escaping acid, this apparatus is composed of three parts, each forming the complement of the other, but which Acan be employed 'sepa x rately either by employing the rstpart with. out either of the two followingpartsor by Yemploying the first two'parts-without the last. These partsare first, the compartment or m Lchamberl in which th-e gases. are saturated; thirdly, the condenser acting by filtration. a L t In the annexeddrawings, Figure lisa sec-` tional plan View of the apparatus, vtaken `on the line C D of Fig. 4; Fig.2 an elevation, be-

section-on the line BA of Fig. 1.-'- Figs'. 3 and- 6 are sectionalviews of modiiica- ,i .-tions inthe form of the preceding construe'y tion ,as hereinafter described. Fig. 4 is a vertical -longitudinal section in elevation on the line E-F of Fig. 1. Fig. 5 is adiagram illus- 1tsrating the iilteri ng' condenser invertical-secl ion. i In Figs. l, 2 and 4 the first part or chamber in which the-gases are saturated is marked with the letter S. It is made of natural V'cut s tone or earthenware, proof against the ac tion of lacids at a temperature of 4about 500- centigrade. A chamber Qin this casing is connected by a hermetically closed joint with an inlet o for, the admission of the gases. Leading from the chamber Q is a Yseries of branching passages qclosed at the top/and at the sides in the same way as the chamber Q but open at the lower par-t so as to allow. the gases to escape at about the level of a layer of acid of any desired depth in the lower part of the chamber.v "The gases escape under the lower edges of the sides of the passages q into I y the passages q', which lead to the recovery column, at the bottom of which is a chamber O. The recovery column is formed of a combination of sii-perposed plates A, B, C, D, the lower ones being composed of natural or artilicial stone, while theupper onesmay be made of similar material or of lead the said plates are perforated Vwith orifices .0 surrounded 'with-raised edges or rims c which retain on the plates a layer of acid of a certain depth.

,Over these rims c, there are placed caps 3,'

which are supported on pins s and deflect the gases passing through the orifices o', provided with rims, anddirect them on to the surface of the liquid in the same way as in the plates of a Derosne column fordistilling alcohol. Overflow passages n lead `the acid from one plate tothe next lower one, and vfrom the bottom plate to the chamber-S. In like manner as in thesaid Derosne column, thevoritices of the overliow passages n for the acid, the heights of which determine or regulate its level, are provided with hydraulic joints to prevent the gases from passing along ber Srrare surrounded'externally with a tight casing p of lead or cast` ironl in order to p recasiugs oli' these several parts are hermetically joined and soldered together.'v Outside l this continuous leadcasing'each plate is separately surrounded by a strong framing or casing u of wood or metal,.which as the lead wears or becomes unsoldered permits of the vplatesbeing raised separately and holdszthe'ir parts together. Over these stone plates, other /vent leakage of the acid. :The edges of the l the same passages' as the liquids. The lower 'l plates of the recovery column and the cham .8

Vplates of lead may be similarly arranged and Y upon thelast or top plate D is placed ademe R of the saine metal conducting the, gases to [the acid entering at Z descends through the /passagesm with vthe hydraulic joints, until it Venters the chamber VS and thence passes to Athe exterior through the invertedv Siphon or trap .met stone ware, porcelainor platinum, whence it passes into a refrigerator ofknown construction.' During this passage the acid becomesmore and more concentrated and at the exterior. While the hot gases risein these f two parts of the apparatus from the cham-v .95 berfO to the dome R''through the orifices o',

roo

same nature as that illustrated in'Figs.' 1, 2'

and 4, with the sole difference'that the current of gases in place of branching orramifying laterally as in passages Qq is caused to Abranch off at different levels. i

In Fig. 3, i2, i12 indicate dams designed to arrest the upper part' of the acid and allow only the lower part of the layerof liquid which is most concentrated topass to the overv flow passages a.

Fig. G represents a slightly diderent construction of the plates of the recovery column, the under side or bottom of one plate forming the cap of the one below.. Moreovcrl do not limit myself to thespecilic constructions shown but can use any modifications in form which will operate as hereinbefore described.

Fig. 5 shows the thirdpart of my apparatus which corresponds with the worm or serpen` tine of an ordinary alembic. This apparatus is constructed with a lead casing C completely closed and into which a pipe P conducts the gases through the cover while another pipe P enables them to escape through the bottom or vice versa. Above the bottom there is a false bottom()5 made of lead pipes `spaced vsufficiently near together'to retain grains i l about the size of rice, of a substance such as coke, powdered glass, pumice stone, earthen; ware or quartz, for example, which is not liableto be attacked by the acids which fill the' casing. V is a steam pipe.

' The operation of my apparatus is as follows: The gases entering ato pass into the chamber Q and passage q, and in Order to escape therefrom the gases are compelled to* rub against `the surface-of the liquid` in a very thin layer of considerable lineal extent. By raising `the level of lthe oriticefor the escape of the acid bythe pipe m,\thelow'er y edges 'i of the sides of the passages maybe immersed in the liquid so as to compel the gases to pass through the latter. In order to economize the power required for moving the gases, and the fuel employed to. produce rthe said power, itis preferable tolimit the extent to which thegases penetrate into theliquid to one or twoA centimeters in a vertical direction. This depth is the best incase thelower edges il are not wetted except when the acid flows at its normal speed and the liow of gases is fully regulated. Although these gasesare usually supplied at from about 400 to 500 centesimal degrees they never cause the liquid to boil but become charged with its vapors. It is a very important condition for the proper working that the gases are saturated with the vapors immediately on their arrival insuch a manner that they are unable totake up all the acid, with which they come in contact at the other parts of the apparatus. In order to produce this saturation with the smallest posi .other reason. In becoming saturated with y vapor the gases immediatelycool down, los `ing from 200J to 300 centigrade, so that Iitis possible to bring the acid` to afmaxixnum degree of concentration. (66 Baume) without subjecting the apparatus to aheat exceeding 170 centigrade, this being `a result hitherto unknown.` The gases consequently do not retain more than from about 17 0 to 200 centigradeat the most and this relatively low temperature greatly contributes tothe preservation" of `the apparatus. Y On? leaving the 'chamber S, the gases proceeding `from the passages q pass into the second part,`nameiy, Qthe recovery column.` As indicated" by its lname, it serves `to-recover and `retain in the :fresh acid, a portion of` the sulfuric acid va- Iin thepassages q. r. i "i `Tliegasesemployed` for the evaporation may consist of` air superheated in `a stove.

:Nevertheless-Ireen employ airwhich has been the arsenic acid` intoarsenious acid` porswith whichthegaseshave been saturated 9o roo - To causethe suction of the gases and aq'uea Y.

ous vapor through theapparatus, I' employ a `jet ot'l steam under pressure in the tube P, {beyond the recovery column, `because the exfhaust prevents `leakage of acid and causes the lead casing to bepressedagainsttheA appa ratus.` This exhausting actioniwas notpra ticable before I discovered tl1e`means'for sep arating the acid from the steaniwithout condens'ng it .by'cooling Thegases escapingat" Y P stil contain sulfuric acid:l They may'be' A employed for variousmanufacturing purposes forwhich theymay be required., It

4not soernployedjl pass themto the-third-part' "ofmy apparatus. i v. i p

The sulfuric acid contained in the gases en tering the condenser at `IF' is not volatile at its temperature and is held suspendedinthe form ol` microscopic drops in the gases. As`

the gases filter through the granularcontents tle drops1 of acid adhere to the grains, trickle down totheibottom of thecondenser and escapethrough the pipe N bywhich they may discharged into the airwithout it being necessary to cool them or sprinkle the'grains of the filter with water.

I claim as my invention-v l. An apparatus for concentrating sulfuric acid by means of hot gases, consisting of a Y chamber S, 'provided with channelsq closed the sheets of acid and become at the top and open at the lower part, the said channels adapted to divide the gases entering at the end of the chamber, channels q', leading from the channels q open at the top, and means for passing sulfuric acid through the vchannels in the chamber in the opposite direction from that taken by the gases, and maintaining the acid in sheets or layers of a desired depth whereby the gases pass through saturated with acid vapors at the first contact with the acid to be treated.

2. In anapparatus for concentrating sulf uric acid by means of hot' gases, the combination of a chamber provided with an inlet for hot gases, channelsq closed at the top but having openings at the lower part, and channels q leading from the channels q, the said channels q being open at the toprwith a recovery column provided with plates adapted to hold acid and having perforations for passage of the gases, and with a discharge pipe P, and means for maintaining the acid in layers throughout the apparatus, substantially as and for the purpose set forth.

3. In an apparatus for concentrating sul'- furic acid by means of hot gases, the combination of a chamberSad-apted to hold alayer of sulfuric acid, and provided with channels q closed at the top, but having openings in the lower part and channels q' leading from the channels q and open at the top, and are#y covery column provided with plates adapted to hold layers of acid and having perforations for the passage nels q', and with a discharge pipe P, with a chest to contain coke or its equivalent provided with an inlet connected to the said pipe P and outlet for the gases, and an outlet for the acid the latter outlet leading back to the recovery column substantially as and for the purposes set forth.

In testimony whereof I have signed my name to this specification in the presence of twosubscribing witnesses.

JACQUES LOUIS KESSLER.

Witnesses:

LEON FRANCKEN, RoBT. M. HooPER.

of the gases from the chan` 

